Aside from being admired spouses of presidential contenders, Michelle Obama and Ann Romney have little in common: different backgrounds, beliefs, life choices and personalities. Yet no matter whether Barack Obama or Mitt Romney wins the presidential election, we will have the same kind of first lady: a warm but cautious woman who endorses safe causes, wears pretty clothing and takes few chances. Anyone looking for an update in the role will probably be disappointed: Ann Romney has said she wants to work with troubled children and people suffering from multiple sclerosis. And fans of vintage Michelle Obama, the frank lawyer we glimpsed in 2008, are unlikely to see that woman return in a second term.

First ladies simply aren’t risk takers like Eleanor Roosevelt or Hillary Clinton anymore, and it’s not because they’re docile throwbacks. With Washington so divided and tweeters hanging on politicians’ every word, no first lady wants to hurt her husband’s presidency, for which she has already sacrificed so much. “I don’t want to be Hillary Clinton. I can’t be that person,” Michelle Obama told an aide after getting to the White House; she had hoped to support her husband’s health care efforts even more visibly than she did but felt she could not risk taking the heat directed at Hillary Clinton for doing so. Last year, according to an adviser, she was planning to delve more deeply into issues like the mental health of veterans and breast-feeding, which would have meant discussing such delicate topics as suicide and breasts. But as 2011 turned into 2012, she mostly stuck to election-friendly causes like jobs for veterans. Will she push harder on those issues or even go beyond them if her husband wins a second term? Perhaps, but the president will always have some crucial fight on his hands, some reason to avoid risking negative headlines.

In fact, Ann Romney might have more leeway to update the role than her Democratic rival. First ladies who are perceived as traditional often find themselves with more room to maneuver. Laura Bush, viewed as a quiet librarian, took on a diplomatically sensitive issue—the Taliban’s treatment of women in Afghanistan—and even more unusually took over her husband’s radio address one week to speak out on the topic. (If Michelle Obama stood in for her husband on a foreign policy statement, can you imagine the uproar that would ensue?)

If the role of first lady seems stagnant, it’s for one reason above all others: She traditionally does not hold a paid job outside the White House—the perceived potential for conflict of interest is too great. That puts her, by definition, several generations behind other women. (Some of us don’t work outside the home, but very few of us are told we cannot.) In 2009 a little girl told Michelle Obama that she wanted to grow up to be first lady. “It doesn’t pay much!” the first lady replied. My own prediction: The role will not budge until our country elects a female president and a first gent. Then no one will care whether the president’s spouse uses the Reagan or Nixon china; the Smithsonian will have to figure out whether to feature his -inaugural-ball tux alongside its famous lineup of gowns. After 200-plus years, the mold of presidential spouse will finally be broken, and a new generation will be able to re-create it, perhaps this time in the images of real American women—and men.

JODI KANTOR is a New York Times correspondent and author of The Obamas, now in paperback, about the couple’s adjustment to the White House and their new roles.